Graft copolymers

ABSTRACT

Anionic graft copolymers and scale inhibition compositions including the anionic graft copolymers in which the anionic graft copolymers include a natural component grafted with an ethylenically unsaturated anionic monomer where the anionic graft copolymer includes 1 or more reacted anhydroglucose units per every 100 anhydroglucose units in the anionic graft copolymer.

The present application claims the benefit to priority to European Patent Application No. 09175465.5, filed Nov. 10, 2009 and U.S. patent application Ser. No. 12/689,844, filed Jan. 19, 2010, which claims the benefit of priority to U.S. patent Ser. No. 12/533,802, filed Jul. 31, 2009, and U.S. patent application Ser. No. 11/458,180, filed Jul. 18, 2006, now U.S. Pat. No. 7,666,963, which claims priority to U.S. Provisional Patent Application Ser. No. 60/701,380, filed Jul. 21, 2005.

FIELD OF THE INVENTION

The present invention relates to graft copolymers. More specifically, the present invention relates to graft copolymers having a natural component grafted onto an ethylenically unsaturated anionic monomer.

BACKGROUND

A number of attempts have been made in the past to use natural materials as polymeric building blocks. These have mainly centered on grafting natural materials such as sugars and starches with synthetic monomers. For example, U.S. Pat. Nos. 5,854,191, 5,223,171, 5,227,446 and 5,296,470 disclose the use of graft copolymers in cleaning applications.

Conventional graft copolymers have been produced by selectively generating initiation sites (e.g., free radicals) for the growth of monomer side chains from the saccharide or polysaccharide backbone (CONCISE ENCYCLOPEDIA OF POLYMER SCIENCE AND ENGINEERING, J. I. Kroschwitz, ed., Wiley-Interscience, New York, p. 436 (1990)). These grafting techniques typically use Fe(II) salts such as ferrous sulfate or Ce(IV) salts (e.g., cerium nitrate or cerium sulfate) to create those initiation sites on the saccharide or polysaccharide backbone (see, e.g., U.S. Pat. No. 5,304,620). Such redox processes are not easily controlled and are inefficient. Also, cerium salts tend to be left in the resulting solution as unwanted byproducts, thereby presenting a potential negative effect on performance. Therefore, there is a need for natural materials as polymeric building blocks that do not provide those problems associated with conventional graft copolymers.

SUMMARY OF THE INVENTION

In an aspect, the invention is directed to an anionic graft copolymer comprising a natural component grafted with an anionic ethylenically unsaturated monomer. The anionic graft copolymer is an anionic graft copolymer comprising a natural component grafted with an ethylenically unsaturated anionic monomer wherein the weight average molecular weight of the natural component is less than 100,000 and wherein the graft copolymer has a mole % of anhydroglucose units of from 10% to less than 75% or the amount of moles of metal ion catalyst/mole peroxide/mole anhydroglucose unit is from 2 to less than 25. In an embodiment according to this aspect, the anionic graft copolymer comprises 5 or more reacted anhydroglucose units per every 100 anhydroglucose units in the anionic graft copolymer.

In another aspect, the invention relates to a graft copolymer blend comprising a graft copolymer and a builder or a chelating agent. The graft copolymer comprises a natural component grafted with an ethylenically unsaturated anionic monomer. The natural component may be lignin or a derivative thereof.

In a further aspect, the invention is directed to an amphoteric graft copolymer. The amphoteric graft copolymer comprises a natural component comprising cationic or anionic moieties grafted with a cationic ethylenically unsaturated monomer or an anionic ethylenically unsaturated monomer or combinations thereof, whereby the resulting graft copolymer is amphoteric.

In yet another embodiment, the invention is directed to a method of determining the concentration of an anionic graft copolymer in an aqueous system. The method comprises reacting a sample of an aqueous graft copolymer comprising a natural component grafted with an anionic ethylenically unsaturated monomer with an effective amount of photoactivator under conditions effective to cause the graft copolymer to absorb with the wavelength in the range of from 300 to 800 nanometers. The method further includes measuring the absorbance of the aqueous sample and comparing the absorbance of the aqueous sample to a predetermined calibration curve of known absorbances and concentrations. The method also includes comparing the absorbance of the aqueous sample to the known concentrations and known absorbances to determine the concentration of the anionic graft copolymer.

In still yet another further embodiment, the invention is directed to a blend comprising an anionic graft copolymer and a builder or a chelating agent. The builder or chelating agent is selected from the group consisting of alkali metal or alkali-metal earth carbonates, alkali metal or alkali earth citrates, alkali metal or alkali earth silicates, glutamic acid N,N-diacetic acid (GLDA), methylglycine N,N-diacetic acid (MGDA) and combinations thereof.

In a further embodiment of this invention, the invention is a cleaning composition containing the lignin graft copolymer in which the natural component is lignin or derivatives thereof, such as lignosulfonates. In still yet another further embodiment, the invention is directed to a scale inhibiting formulation comprising one or more graft copolymers according to the invention and to a method of inhibiting scale formation in aqueous systems wherein the composition has a greater than 80% carbonate inhibition at a 100 ppm dosage level of the anionic graft copolymer in an aqueous system.

DETAILED DESCRIPTION OF THE INVENTION

Graft copolymers are produced by selectively generating initiation sites (e.g., free radicals) for the growth of monomer side chains from an existing polymer backbone (CONCISE ENCYCLOPEDIA OF POLYMER SCIENCE AND ENGINEERING, J. I. Kroschwitz, ed., Wiley-Interscience, New York, p. 436 (1990)). Therefore, graft copolymers are defined as a backbone of a natural component with one or more side chains derived from synthetic monomers.

The term “natural component” as used herein, means any backbone obtained from plant sources directly or by enzymatic or fermentation processes from which a free radical can be abstracted. In an embodiment of the invention, these natural components include, but are not limited, to small molecules such as glycerol, citric acid, lactic acid, tartaric acid, gluconic acid, ascorbic acid, glucoheptonic acid. The natural components may also include saccharides or derivatives thereof. Suitable saccharides include, for example, monosaccharides and disaccharides such as sugars, as well as larger molecules such as oligosaccharides and polysaccharides (e.g., maltodextrins, pyrodextrins and starches). In an embodiment of the invention, the natural component is corn syrup, maltodextrin, pyrodextrin or a low molecular weight starch or oxidized starch. It has been found that the grafting reaction does not work well when the natural component is not soluble in the reaction solvent which in most cases is water. For example, high molecular weight starches, such as those having molecular weights in the millions or those in granular form, are water dispersable and not water soluble. Accordingly, in certain embodiments of the invention, the average molecular weight of the natural component is less than about 500,000 based on a starch standard. Starches having such exemplary molecular weights are water soluble. In another embodiment, the weight average molecular weight (Mw) of the natural component may be less than about 100,000. In yet another embodiment, the weight average molecular weight of the natural component may be less than about 50,000. In yet another embodiment, the weight average molecular of the natural component may be less than about 10,000.

The molecular weight of the polysaccharide is determined by the procedure outlined below:

-   -   Eluent: 0.025M NaH₂PO₄, 0.025 M Na₂HPO₄ and 0.01M of Sodium         Azide in HPLC grade water. This solution was filtered through a         0.2 μm filter.     -   Columns: 1×G6000PW×1 7.8 mm×30 cm, G4000PW×1 7.8×30 cm,         G3000PW×1         -   7.8 mm×30 cm, Guard column is TSKgel Guard PWx1 6.0 mm×4 cm             (all made by Tosoh Bioscience)         -   The column bank was controlled to 5° C. above ambient             temperature. Usually 30° C.     -   Flow Rate: 1.0 ml/min     -   Detector: Refractive Index, Waters® Model 2414 Temperature         controlled to 30° C.     -   Pump/Autosampler: Waters® e2695 Separation Module. Sample         compartment temperature controlled to 25° C.     -   Primary Standards: HETA (Hydroxyethylstarch). Available from         American Polymer Standards Corporation. (www.ampolymer.com) 5         standards. Prepare a 0.1% w/w in the mobile phase of each of the         following:

1. Mw 9,600 Mn 5,400 2. Mw 25,900 Mn 10,600 3. Mw 51,100 Mn 34,300 4. Mw 114,300 Mn 58,000 5. Mw 226,800 Mn 95,900

-   -   Sample Preparation: The samples were prepared by dissolving the         polymer in the mobile phase at a 0.1% concentration.     -   Injection Volume: 450 μl for the standard and sample.         -   The standards are injected and a first or second order             calibration curve is built.         -   The curve with the best fit and within the range of the             molecular weight of the unknown sample was then chosen.     -   Software: Empower® 2 by Waters Corporation         -   A calibration curve is first built with the samples of the             standards. The molecular weight of the unknown sample is             then determined by comparing its elution time with the             elution time of the standards.

The term “natural components” also include cellulose and cellulose derivatives, as well as inulin and its derivatives, such as carboxymethyl inulin. The cellulosic derivatives include plant heteropolysaccharides commonly known as hemicelluloses which are by products of the paper and pulp industry. Hemicelluloses include xylans, glucuronoxylans, arabinoxylans, glucomannans, and xyloglucans. Xylans are the most common heteropolysaccharide and are preferred. Furthermore, these natural components also include lignin and its derivatives, such as lignosulfonates. In an embodiment of the invention, cellulosic derivatives such as heteropolysaccharides, such as xylan and lignin and/or derivatives thereof, may be present in an amount of from about 0.1% to about 98% by weight, based on the total amount of the graft copolymer. In an embodiment of this invention the natural components may be maltodextrins, pyrodextrins and chemically modified versions of maltodextrins and pyrodextrins. In another embodiment, the natural components may be cellulose of inulin or chemically modified cellulose or inulin or a heteropolysaccharide such as xylan or a lignin derivative, such as a lignosulfonate.

As used herein, the term “anionic ethylenically unsaturated monomer” means an ethylenically unsaturated monomer which is capable of introducing a negative charge to the anionic graft copolymer. These anionic ethylenically unsaturated monomers can include, but are not limited to, acrylic acid, methacrylic acid, ethacrylic acid, α-chloro-acrylic acid, α-cyano acrylic acid, β-methyl-acrylic acid (crotonic acid), α-phenyl acrylic acid, β-acryloxy propionic acid, sorbic acid, α-chloro sorbic acid, angelic acid, cinnamic acid, p-chloro cinnamic acid, β-styryl acrylic acid (1-carboxy-4-phenyl butadiene-1,3), itaconic acid, maleic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, fumaric acid, tricarboxy ethylene, muconic acid, 2-acryloxypropionic acid, 2-acrylamido-2-methyl propane sulfonic acid, vinyl sulfonic acid, sodium methallyl sulfonate, sulfonated styrene, allyloxybenzene sulfonic acid, vinyl phosphonic acid and maleic acid. Moieties such as maleic anhydride or acrylamide that can be derivatized (hydrolyzed) to moieties with a negative charge are also suitable. Combinations of anionic ethylenically unsaturated monomers can also be used. In an embodiment of the invention, the anionic ethylenically unsaturated monomer may preferably be acrylic acid, maleic acid, methacrylic acid, itaconic acid, 2-acrylamido-2-methyl propane sulfonic acid or mixtures thereof.

The anionic graft copolymer may contain a minimum of 1, in another embodiment 20 and in yet another embodiment 50 weight percent of the natural component based on the weight of the graft copolymer. The graft copolymer compositions may contain a maximum of 99, more preferably 95 and most preferably 90 weight percent of the natural component based on the weight of the graft copolymer.

The natural components suitable for use in the present invention can be used as obtained from their natural source or they can be chemically modified. Chemical modification includes hydrolysis by the action of acids, enzymes, oxidizers or heat, esterification or etherification. The modified natural components, after undergoing chemical modification may be cationic, anionic, non-ionic or amphoteric or hydrophobically modified or hydrophilically modified. In an embodiment of the invention, the graft copolymer may optionally be formed by polymerization catalyzed by, for example, a metal based radical initiator system, such as initiators based on Fe or Ce.

In an aspect of the present invention, the invention relates to an anionic graft copolymer. In an embodiment according to this aspect, the anionic graft copolymer comprises a natural component grafted with an anionic ethylenically unsaturated monomer. In a further embodiment of the invention, the anionic graft copolymer is a high density anionic graft copolymer. In accordance with the present invention a “high density” anionic graft copolymer has 1 or more, in another embodiment 2 or more, in another embodiment 3 or more, or in yet another embodiment 4 or more reacted anhydroglucose units per every 100 anhydroglucose units in the anionic graft copolymer.

As used herein, the term “reacted anhydroglucose unit” means any anhydroglucose unit in the anionic graft copolymer that does not hydrolyze to glucose. These reacted anhydroglucose units include those that have synthetic chains attached to them as well as other side reactions that can occur in the process such as combination of the anhydroglucose radical with other radicals etc.

It has been found that certain molecular weight of the natural component allows the number of reacted anhydroglucose units to be obtained. The weight average molecular weight of the natural component may be less than 100,000, in another embodiment less than 50,000 and in yet another embodiment less than 10,000. In one embodiment if the natural component is a low molecular weight starch than the DE is preferably greater than 5 and more preferably greater than 8 and most preferably greater than 9.

The graft copolymers are a reaction of the natural component, at least one ethylenically unsaturated anionic monomer and an initiating system. The initiating system is usually a combination of a peroxide such as hydrogen peroxide and a metal ion catalyst such as Fe (II). In one embodiment, when the natural component is a polysaccharide, the number of reacted anhydroglucose units per 100 anhydroglucose units of 5 or greater is obtained when the mole % of anhydroglucose units is a maximum of 75%, in another embodiment a maximum of 67% and in yet another embodiment is a maximum of 60% of the total moles of anhydroglucose. In embodiments of the invention, the mole % of anhydroglucose units is a minimum of 10%, in another embodiment a maximum of 15% and in yet another embodiment is a maximum of 20% of the total moles of anhydroglucose. In still yet another embodiment, when the natural component is a polysaccharide, the number of reacted anhydroglucose units per 100 anhydroglucose units of 5 or greater is obtained when the μ moles metal ion catalyst per mole peroxide per mole anhydroglucose unit is a maximum of 25, and in yet another embodiment a maximum of 20 and in an even further embodiment is a maximum of 15. In another embodiment, the μ moles metal ion catalyst per mole peroxide per mole anhydroglucose unit is a minimum of 2, and in yet another embodiment a minimum of 5 and in an even further embodiment is a minimum of 8. Embodiments of the invention may also include combinations of these aforementioned maxima and minima. In another embodiment, the number of reacted anhydroglucose units per 100 anhydroglucose units of 5 or greater is obtained when the mole % of anhydroglucose units is of from 10% to less than 75%, in another embodiment of from 15% to less than 67% and in yet another embodiment of from 20% to less than 60% of the total moles of anhydroglucose and the μ moles metal ion catalyst per mole peroxide per mole anhydroglucose unit is from 2 to less than 25, in another embodiment from 5 to less than 20 and in yet another embodiment from 8 to less than 15.

In one embodiment of the invention, the natural component of the high density graft copolymer is selected from oxidized starch, maltodextrin, corn syrup, disaccharide or monosaccharide. The anionic ethylenically unsaturated monomer in the high density anionic graft copolymer is selected from acrylic acid, methacrylic acid, itaconic acid, maleic acid, 2-acrylamido-2-methyl propane sulfonic acid or mixtures thereof of their salts. In a further embodiment, the anionic ethylenically unsaturated monomer in the high density anionic graft copolymer is acrylic acid or its salts. In another embodiment, the weight average molecular weight (Mw) of the natural component of the high density graft copolymer may be less than about 100,000. In yet another embodiment, the weight average molecular weight of the natural component of the high density graft copolymer may be less than about 50,000. In yet another embodiment, the weight average molecular of the natural component of the high density graft copolymer is less than about 10,000. In an embodiment of the invention, the minimum weight average molecular weight of the natural component is 1000.

The high density graft copolymers are useful in various applications, including carbonate and phosphate scale inhibitors in aqueous systems. It has been found that suitable scale inhibiting graft copolymers will provide at least 80% scale inhibition in a carbonate inhibition test performed according to the procedure detailed below:

Calcium Carbonate Inhibition Test Protocol:

A liter of Hardness Solution and an Alkalinity Solution was prepared in deionized (DI) water using the ingredients and amounts listed in Tables 1 and 2:

TABLE 1 Hardness Solution Compound g/L MgCl₂ * 6H₂O 25.0836  CaCl₂ * 2H₂O 36.6838 LiCl 0.6127

TABLE 2 Alkalinity Solution Compound g/L NaHCO₃ 48.9863 Na₂CO₃ 7.0659

A 100 ml polymer solution was prepared by adding 1% active polymer diluted with DI water.

A sample solution containing the polymer to be tested was prepared in 100 ml volumetric flasks by adding 1.2 grams Hardness Solution, desired level of polymer solution (100 microliters polymer solution=10 ppm polymer in the aqueous treatment solution), and 1.2 grams Alkalinity Solution and using DI water to make up the total solution to 100 ml. A blank solution was prepared as the sample solution above but without the polymer. A total solution was also prepared as the sample solution above but without the polymer and replacing alkalinity with DI water. The samples were placed uncapped in a shaker oven (Classic C24 Incubator Shaker model from New Brunswick Scientific Co., Inc., Edison, N.J.) at 50 C, 250 rpm for 17 hours.

The samples were removed, allowed to cool to ambient and then 1 mL of each sample was filtered through 0.2 micron filter syringes and diluted to 10 grams total with 2.5% nitric acid solution.

The sample solution, blank solution and total solutions were analyzed for calcium and lithium via ICP-OES (Optima 2000DV model from Perkin Elmer Instruments, Covina, Calif., with a low standard of 1 ppm Li, 10 ppm Ca, and a high standard of 2 ppm Li, 20 ppm Ca). After accounting for the dilution during the filtration process, the % calcium carbonate inhibition was determined by:

$\frac{\lbrack{Ca}\rbrack_{Sample} - \lbrack{Ca}\rbrack_{Blank}}{\frac{\lbrack{Li}\rbrack_{Sample}}{\lbrack{Li}\rbrack_{Total}}*\left( {\lbrack{Ca}\rbrack_{Total} - \lbrack{Ca}\rbrack_{Blank}} \right)} \times 100\%$

Where [Ca]_(Sample) [Ca]_(Blank) [Ca]_(Total) is the concentration of calcium in the sample, blank and total solution respectively and [Li]_(Sample) [Li]_(Total) is the concentration of Lithium in the sample and total solution respectively.

This was the procedure that was used to measure carbonate inhibition in the examples of this patent application.

In embodiments of the invention, the high density graft copolymers generally provide greater than 80% carbonate inhibition at a 100 ppm dosage level of the polymer in an aqueous system. In further embodiments, the high density graft copolymers provide better than 80% carbonate inhibition at a 25 ppm dosage level of the polymer in an aqueous system. In still further embodiments, the high density graft copolymers will provide better than 80% carbonate inhibition at a 15 ppm dosage level of the polymer in an aqueous system.

In a further aspect of the invention, the anionic graft copolymer is a lignin graft copolymer in which the natural component is lignin and its derivatives, such as lignosulfonates. In a further embodiment of this invention, a cleaning composition comprises a lignin graft copolymer as a constituent of the cleaning composition.

The anionic graft copolymer may contain a minimum of 1, in another embodiment 20 or more, in another embodiment greater than or equal to 50 in another embodiment 60, in another embodiment 70, and in yet another embodiment 80 weight percent of the natural component based on the weight of the graft copolymer. The graft copolymer compositions may contain a maximum of 99, in another embodiment a maximum of 95 and in another embodiment a maximum of 90 weight percent of the natural component based on the weight of the graft copolymer.

In a further embodiment, the anionic graft copolymer contains from about 80 to 99 percent of natural component by weight based on the amount of anionic graft copolymer. In one embodiment, the anionic ethylenically unsaturated monomer of the low anionic graft copolymer is carboxylated only but not sulfonated and may preferably be acrylic acid, maleic acid, methacrylic acid, itaconic acid, or mixtures and salts thereof.

Compositions comprising the anionic graft copolymers of the present invention are useful for a number of different applications including, but not limited to, cleaning, laundry, automatic dish washing (ADW), superabsorbent, fiberglass binder, rheology modifier, various oilfield applications, water treatment, dispersant, cementing and concrete compositions. For cleaning applications, the compositions may include, but are not limited to, detergent, fabric cleaner, automatic dishwashing detergent, rinse aids, glass cleaner, fabric care formulation, fabric softener, flocculants, coagulants, emulsion breakers, alkaline and acidic hard surface cleaners, laundry detergents and others. The compositions can also be used to clean surfaces in industrial and institutional cleaning applications. In an exemplary embodiment for automatic dishwashing detergent formulations, such formulations include phosphate, low phosphate and “zero” phosphate built formulations, in which the detergent is substantially free of phosphates. As used herein, low phosphate means less than 1500 ppm phosphate in the wash, in another embodiment less than about 1000 ppm phosphate in the wash, and in still another embodiment less that 500 ppm phosphate in the wash.

The anionic graft copolymers can also be used as scale control agents in cleaning, laundry, ADW, oilfield applications, water treatment, and in any other aqueous systems where scale buildup is an issue. The scales controlled include, but are not limited to, carbonate, sulfate, phosphate or silicate based scales such as calcium sulfate, barium sulfate, calcium ortho and polyphosphate, tripolyphosphate, magnesium carbonate, magnesium silicate and others.

In further embodiments, the anionic graft copolymer compositions can also be used as dispersants in cleaning, oilfield and water treatment applications, paint and coatings, paper coatings and other applications. These anionic graft copolymers can be used to disperse particulates, nanoparticulates, nanomaterials and the like including, but not limited to, minerals, clays, salts, metallic ores, metallic oxides, dirt, soils, talc, pigments, titanium dioxide, mica, silica, silicates, carbon black, iron oxide, kaolin clay, calcium carbonate, synthetic calcium carbonates, precipitated calcium carbonate, ground calcium carbonate, precipitated silica, kaolin clay or combinations thereof.

As used herein, the term “anionic graft copolymer adjunct ingredient” means ingredients that are typically used in formulations including the anionic graft copolymer. These anionic graft copolymer adjunct ingredients include, but are not limited to, water, surfactants, builders, phosphates, sodium carbonate, citrates, enzymes, buffers, perfumes, anti-foam agents, ion exchangers, alkalis, anti-redeposition materials, optical brighteners, fragrances, dyes, fillers, chelating agents, fabric whiteners, brighteners, sudsing control agents, solvents, hydrotropes, bleaching agents, bleach precursors, buffering agents, soil removal agents, soil release agents, fabric softening agent, opacifiers, water treatment chemicals, corrosion inhibitors, orthophosphates, zinc compounds, tolyltriazole, minerals, clays, salts, metallic ores, metallic oxides, talc, pigments, titanium dioxide, mica, silica, silicates, carbon black, iron oxide, kaolin clay, modified kaolin clays, calcium carbonate, synthetic calcium carbonates, fiberglass, cement and aluminum oxide. The surfactants can be anionic, non-ionic, such as low foaming non-ionic surfactants, cationic or zwitterionic. In an embodiment of the invention, the chelants may be glutamic acid N,N-diacetic acid (GLDA) and methylglycine N,N-diacetic acid (MGDA) and others.

Some other oilfield uses for the anionic graft copolymers of this invention include additives in cementing, drilling muds, dispersancy, fluid loss, permeability modification and spacer fluid applications. Often, the water encountered in oilfield applications is sea water or brines from the formation. The water encountered in the oilfield can be very brackish. Hence, the polymers may also desirably be soluble in many brines and brackish waters. These brines may be sea water which contains about 3.5 percent NaCl by weight or more severe brines that contain, for example, up to 3.5% KCl, up to 25% NaCl and up to 20% CaCl₂. Therefore, the polymers should be soluble in these systems for them to be effective as, for example, scale inhibitors. It has further been found that the higher the solubility of the anionic graft copolymer adjunct in the brine, the higher the compatibility. The composition of synthetic seawater, moderate and severe calcium brines which are typical brines encountered in the oilfield is listed in Table 3 below.

TABLE 3 Typical brines encountered in the oilfield. Brine preparation grams per liter ppm Brine number and description NaCl CaCl₂•2H₂O MgCl₂•6H₂O Na Ca Mg 1 synthetic seawater 24.074 1.61 11.436 9471 439 1368 2 moderate calcium brine 63.53 9.19 24992 2506 0 3 severe calcium brine 127.05 91.875 49981 25053 0 As described in Table 3, sea water contains around 35 grams per liter of a mixture of salts. The moderate and severe calcium brines contain around 70 and 200 grams per liter of a mixture of salts respectively.

In oil field applications, the scale inhibitor may be injected or squeezed or may be added topside to the produced water. Accordingly, embodiments of the invention also include mixtures of the anionic graft copolymer and a carrier fluid. The carrier fluid may be water, glycol, alcohol or oil. Preferably, the carrier fluid is water or brines or methanol. Methanol is often used to prevent the formation of methane hydrate (also known as methane clathrate or methane ice) structures downhole. In another embodiment of this invention, the anionic graft copolymers may be soluble in methanol. Thus, the scale inhibiting polymers can be introduced in to the well bore in the methanol line. This is particularly advantageous since there is fixed number of lines that run in to the wellbore and this combination eliminates the need for another line.

In an embodiment of the invention the anionic graft copolymer compositions can be uniformly mixed or blended with builders or chelating agents and then processed into powders or granules. For example, compositions including the anionic graft copolymer compositions of the present invention may include alkali metal or alkali-metal earth carbonates, citrates or silicates as exemplary builders suitable for use in detergent formulations. The term alkali metals are defined as the Group IA elements, such as lithium, sodium and potassium, whereas the alkali-metal earth metals are the Group IIA elements which include beryllium, magnesium and calcium.

Powders as used herein are defined as having an average particle size of less than about 300 microns, whereas granules are particles of an average size of greater than about 300 microns. By uniformly mixing or blending the anionic graft copolymer with the builder or chelating agent, the particles or granules provide less hygroscopic properties and afford easier handling and free flowing powders. Free flowing as used in this application are powders or granules that do not clump or fuse together.

In still yet another aspect, the invention relates to amphoteric graft copolymers containing both anionic and cationic moieties. The anionic moieties can be on the natural component which is grafted with a cationic ethylenically unsaturated monomer or the cationic moieties can be on the natural component which is grafted with an anionic ethylenically unsaturated monomer or combinations thereof. When the natural component is a polysaccharide, the anionic material can be an oxidized starch and the cationic ethylenically unsaturated monomer may be diallyldimethylammonium chloride. Alternatively, the oxidized starch itself may first be reacted with cationic substituent such as 3-chloro-2-hydroxypropyl) trimethylammonium chloride and then reacted with an anionic or cationic ethylenically unsaturated monomer or mixtures thereof. In another preferred embodiment, a cationic starch may be grafted with an anionic ethylenically unsaturated monomer. Finally, the cationic ethylenically unsaturated monomer and anionic ethylenically unsaturated monomer may be grafted on to the natural component.

As used herein, the term “cationic ethylenically unsaturated monomer” means an ethylenically unsaturated monomer which is capable of introducing a positive charge to the non-amphoteric graft copolymer. In an embodiment of the present invention, the cationic ethylenically unsaturated monomer has at least one amine functionality. Cationic derivatives of these amphoteric graft copolymer may be formed by forming amine salts of all or a portion of the amine functionality, by quaternizing all or a portion of the amine functionality to form quaternary ammonium salts, or by oxidizing all or a portion of the amine functionality to form N-oxide groups.

As used herein, the term “amine salt” means the nitrogen atom of the amine functionality is covalently bonded to from one to three organic groups and is associated with an anion.

As used herein, the term “quaternary ammonium salt” means that a nitrogen atom of the amine functionality is covalently bonded to four organic groups and is associated with an anion. These cationic derivatives can be synthesized by functionalizing the monomer before polymerization or by functionalizing the polymer after polymerization. These cationic ethylenically unsaturated monomers include, but are not limited to, N,N dialkylaminoalkyl(meth)acrylate, N-alkylaminoalkyl(meth)acrylate, N,N dialkylaminoalkyl(meth)acrylamide and N-alkylaminoalkyl(meth)acrylamide, where the alkyl groups are independently C₁₋₁₈ cyclic compounds such as 1-vinyl imidazole and the like. Aromatic amine containing monomers such as vinyl pyridine may also be used. Furthermore, monomers such as vinyl formamide, vinyl acetamide and the like which generate amine moieties on hydrolysis may also be used.

Cationic ethylenically unsaturated monomers that may be used are the quarternized derivatives of the above monomers as well as diallyldimethylammonium chloride also known as dimethyldiallylammonium chloride, (meth)acrylamidopropyl trimethylammonium chloride, 2-(meth)acryloyloxy ethyl trimethyl ammonium chloride, 2-(meth)acryloyloxy ethyl trimethyl ammonium methyl sulfate, 2-(meth)acryloyloxyethyltrimethyl ammonium chloride, N,N-Dimethylaminoethyl (meth)acrylate methyl chloride quaternary, methacryloyloxy ethyl betaine as well as other betaines and sulfobetaines, 2-(meth)acryloyloxy ethyl dimethyl ammonium hydrochloride, 3-(meth)acryloyloxy ethyl dimethyl ammonium hydroacetate, 2-(meth)acryloyloxy ethyl dimethyl cetyl ammonium chloride, 2-(meth)acryloyloxy ethyl diphenyl ammonium chloride and others.

For the amphoteric graft copolymers, the preferred cationic ethylenically unsaturated monomer is N,N-dimethylaminoethyl methacrylate, tert-butylaminoethylmethacrylate, N,N-dimethylaminopropyl methacrylamide or dimethyldiallylammonium chloride and the preferred anionic ethylenically unsaturated monomer is acrylic acid, methacrylic acid, maleic acid, itaconic acid, 2-acrylamidomethyl-2-propane sulfonic acid, mixtures thereof and their salts.

These amphoteric graft copolymers containing both anionic and cationic moieties are particularly useful in detergent formulations as dispersants and cleaning aids. It is understood that these polymers will contain both a natural component grafted with an anionic or cationic ethylenically unsaturated monomer. When the cationic moieties are on the natural component, the cationic moieties are preferably present in the range of 0.001 to 40 mole % of the anionic moieties, more preferably the cationic moieties are present in the range of 0.01 to 20 mole % of the anionic moieties, and most preferably the cationic moieties are present in the range of 0.1 to 10 mole % of the anionic moieties. Polymers formed from a cationic ethylenically unsaturated monomer tend to have poor toxicological and environmental profiles. Therefore, it is necessary to minimize the level of cationic ethylenically unsaturated monomer in the amphoteric graft copolymer. In the amphoteric graft copolymer, when a cationic ethylenically unsaturated monomer is grafted on the natural component, the cationic ethylenically unsaturated monomer is preferably present up to 10 mole % of the anionic ethylenically unsaturated monomer, more preferably the cationic ethylenically unsaturated monomer is preferably present up to 6 mole % of the anionic ethylenically unsaturated monomer, and most preferably the cationic ethylenically unsaturated monomer is preferably present up to 5 mole % of the anionic ethylenically unsaturated monomer.

In still yet another aspect, the invention relates to highly renewable graft copolymers derived from renewable monomers. For purposes of this invention, “renewable monomers” can be any ethylenically unsaturated monomers produced from natural sources. Examples of renewable monomers include itaconic acid produced from corn or acrylamide produced by fermentation as well as acrylic acid and methacrylic acid from non petroleum based feedstocks. The acrylamide can be hydrolyzed to acrylic acid after the polymerization to introduce anionic functionality. One skilled in the art will recognize that monomers produced from natural sources increase the renewable carbon content of the polymers of this invention. The homopolymers of itaconic acid have relatively large amounts of unreacted monomer. These homopolymers tend to have residual itaconic acid levels of greater than 20 and some times greater than 50 weight percent of the itaconic acid added to the reactor. Surprisingly, it has been found that itaconic acid based graft copolymers tend to graft on to a natural component better than reacting with itself and have a residual itaconic acid level of less than 10% and in another embodiment less than 5% of the itaconic acid added to the reaction. This is an advantage since all of the itaconic acid can contribute to the performance of the polymer. In one embodiment, the preferred natural components of the highly renewable graft copolymers are monosaccharides, disaccharides, oligosaccharides and polysaccharides. In a further embodiment of the invention, the natural component is a corn syrup, maltodextrin, pyrodextrin or a low molecular weight starch or oxidized starch. In another embodiment, the weight average molecular weight (Mw) of the natural component of the highly renewable graft copolymers may be less than about 100,000. In yet another embodiment, the weight average molecular weight of the natural component of the highly renewable graft copolymers may be less than about 50,000. In yet another embodiment, the weight average molecular of the natural component of the highly renewable graft copolymers may be less than about 10,000. In a further embodiment of the invention, highly renewable graft copolymer contains greater than 20, in another embodiment greater than 40 and in yet another embodiment greater than 50 percent of natural component by weight of the highly renewable graft copolymer. In a further embodiment of the invention, highly renewable graft copolymer contains less than 98, in another embodiment less than 95 and in yet another embodiment less than 90 percent of natural component by weight of the highly renewable graft copolymer.

In yet another embodiment, the present invention provides an ester graft copolymer comprising a natural component grafted with at least one ester monomer. In an embodiment of the invention, the ester monomer is derived from a carboxylic acid. In a further embodiment, the at least one ester monomer may be chosen from monomethylmaleate, dimethylmaleate, monomethylitaconate, dimethylitaconate, monoethylmaleate, diethylmaleate, monoethylitaconate, diethylitaconate, monobutylmaleate, dibutylmaleate, monobutylitaconate and dibutylitaconate. In a further embodiment, the at least one ester monomer may be chosen from hydroxyethyl(meth)acrylate, hydroxyproyl(meth)acrylate and hydroxybutyl(meth)acrylate

In a further aspect, when the natural component is a saccharide or polysaccharide, the invention relates to a method of determining the concentration of an anionic graft copolymer in an aqueous system. In embodiments according to this aspect, the method comprises reacting a sample of an anionic graft copolymer with an effective amount of photoactivator under conditions effective to cause the anionic graft copolymer to absorb with the wavelength in the range of from 300 to 800 nanometers.

In an embodiment, the method is detecting the level of an anionic graft copolymer comprising a saccharide or polysaccharide grafted with at least one anionic ethylenically unsaturated monomer in an aqueous solution. The method further includes measuring the absorbance of the aqueous sample and comparing the absorbance of the aqueous sample to a predetermined calibration curve of known absorbances and concentrations. By comparing the aqueous sample to the known concentrations and know absorbances of known anionic graft copolymers, the concentration of the aqueous sample is determined. Once the concentration of the anionic graft copolymer in the aqueous sample is determined, the amount of additional copolymer that would be needed to maintain the desired level of copolymer in the aqueous system can be adjusted accordingly. This eliminates overdosing the aqueous system with excess copolymer and minimizes waste and costs.

In yet another aspect, when the natural component is a lignin derivative such as lignosulfonate, the lignosulfonate anionic graft copolymer can be detected by passing the aqueous system containing dilute solutions of the polymer through a uv/vis system. A calibration curve can be generated where the uv/vis absorbances are measured of the polymer of known concentrations. The uv/vis absorbance of the unknown polymer concentration is then measured and compared to the calibration curve to determine the concentration of the polymer.

EXAMPLES

The following examples are intended to exemplify the present invention but are not intended to limit the scope of the invention in any way. The breadth and scope of the invention are to be limited solely by the claims appended hereto.

Example 1

102.4 grams of maltodextrin STAR-DRI 100DE 10 (spray-dried maltodextrin, Mw 62743, Mn 21406, available from Tate and Lyle, Decatur, Ill.) and 79.9 grams of itaconic acid (derived from corn available from Miami Chemicals) were initially dissolved in 97.4 grams of water in a reactor and heated to 98° C. 0.008 grams of ferrous ammonium sulfate hexahydrate and 39.3 grams of 50% sodium hydroxide solution were added to the solution in the reactor. A monomer solution containing 4.92 grams of acrylic acid and 150 grams of water was subsequently added to the reactor over a period of 4 hours. An initiator solution comprised of 19.4 grams of 35% hydrogen peroxide solution and 150 grams of water was added to the reactor at the same time as the monomer solution over a period of 4 hours. The reaction product was held at 98° C. for an additional 60 minutes. The final product was an amber colored solution and the residual itaconic acid was 534 ppm. The amount of residual itaconic acid was found to be 0.5% of the monomer added to the reaction.

Example 2 Determination of Reacted Anhydroglucose Units Per Every 100 Anhydroglucose Units in the Anionic Graft Copolymer

Hydrolysis of the Samples

Prior to the glucose determination, the maltodextrins and the various copolymers were hydrolysed following the following sulfuric acid procedure. About 500 mg sample was weighed in an acid digestion bomb equipped with 30 ml teflon insert (Parr Instruments) and diluted with 1 ml 70% H₂SO₄ followed by addition of approximately 3 ml of distilled (milliQ) water. The mixture was heated to 90° C. for about 5 hours. This hydrolysis was carried out in duplicate for all samples.

Determination of Glucose

The amount of glucose in the various samples was determined by HPLC, using glycerol as internal standard. The HPLC conditions were as follows:

Column: IOA 1000 (Grace Alltech) (300*7.8 mm)

Column temperature: 50° C.

Mobile phase: Sulfuric acid 0.01N

Flow: 0.4 ml/min

Detection: Refractive Index

Injection volume: 20 μl.

Determination of Solid Content for the Maltodextrins

The solid content was determined by treating a known amount of sample in a Mettler Toledo HG63 halogen dryer for 20 minutes. Each analysis was carried out in duplicate.

Degree of Hydrolysis of the Maltodextrin

The glucose is representative of the degree of hydrolysis of the maltodextrin part of the polymer. A theoretical percentage of glucose for a 100% hydrolysis can be calculated for the various samples, as for each of them the exact weight of maltodextrin is known. This theoretical value is the weight of maltodextrin corrected for the addition of one molecule of water per anhydroglucose unit, i.e.:

GLU_(th)=[weight of maltodextrin]×180/162

The efficiency of the hydrolysis by the sulfuric acid procedure was established using the starting maltodextrins Star Dri 100 (DE 10) and Star Dri 180 (DE 18). The results are summarized in Table 4, together with the solid content of the samples. The solid content was used to correct for water adsorbed on the polymer.

TABLE 4 Efficiency of sulfuric acid hydrolysis. Solid Sample code / content Weight GLU_(th) * GLU_(HPLC) Recovery Component (%) (mg) (mg) (mg) (%) Star Dri 100 (DE 10) 93.8 42.4 44.2 43.1 97.5 40.2 41.9 41.0 97.9 Star Dri 180 (DE 18) 93.1 38.6 39.8 40.1 100.8 42.5 43.9 43.9 100.0 * Corrected for water content

The recovery is slightly lower for the Star Dri 100 (DE 10) sample, but the efficiency of the method is very reasonable. It is important to account for the fact that the maltodextrin samples also contain a certain amount of water.

Hydrolysis of the Copolymers

The copolymer of Example 1 was hydrolyzed using the procedure detailed above. The copolymer of Example 1 contained 102 grams of DE 10 maltodextrin in approximately 643.2 grams of polymer solution. This weight of maltodextrin is corrected for the water content mentioned in Table 4,

TABLE 5 Determination of glucose in hydrolyzed copolymer samples (% m/m) Number of reacted Weight Weight anhydroglucose percent of percent units glucose in of glucose per every 100 Weight percent polymer that is anhydroglucose of theoretical solution as unsub- units in amount of determined stituted the polymer Glucose in the by sulfuric (% unsub- (100 − % polymer acid stituted unsubstituted Polymer solution GLU_(th)* hydrolysis GLU) GLU) Example 1 14.9 13.1 88.1 11.9 * Corrected for the water content of the starting maltodextrins

The weight percent of glucose that is unsubstituted was calculated from the results of the sulfuric acid hydrolysis and GLU_(th). Assuming 100% efficiency of the hydrolysis, since only unsubstituted anhydroglucose units will be hydrolysed to glucose, the ratio between the 2 values is the percentage of these unsubstituted units in the copolymers, i.e. anhydroglucose units that are unreacted. The number of reacted anhydroglucose units per every 100 anhydroglucose units in the polymer is then 100 minus the % unsubstituted GLU.

Example 3

102.4 grams of maltodextrin (STAR-DRI 100 DE 10 spray-dried maltodextrin available from Tate and Lyle, Decatur, Ill.) and 44.4 grams of itaconic acid were initially dissolved in 97.4 grams of water in a reactor and heated to 98° C. 0.008 grams of ferrous ammonium sulfate hexahydrate and 21.8 grams of 50% sodium hydroxide solution were added to the solution in the reactor. A monomer solution containing 24.6 grams of acrylic acid and 150 grams of water was subsequently added to the reactor over a period of 4 hours. An initiator solution comprised of 19.4 grams of 35% hydrogen peroxide solution and 150 grams of water was added to the reactor at the same time as the monomer solution over a period of 4 hours. The reaction product was held at 98° C. for an additional 60 minutes. The final product was a light amber colored solution and the residual itaconic acid was 204 ppm. The number of reacted anhydroglucose units per every 100 anhydroglucose units was found to be 13.5 using the procedure detailed in Example 2. The amount of residual itaconic acid was found to be 0.3% of the monomer added to the reaction.

Example 4

112.6 grams of corn syrup (STAR-DRI 42R DE 42, weight average molecular weight (Mw) 906, number average molecular weight (Mn) 312, spray-dried corn syrup available from Tate and Lyle, Decatur, Ill.) and 24.2 grams of maleic anhydride were initially dissolved in 102 grams of water in a reactor and heated to 98° C. 0.008 g of ferrous ammonium sulfate, 24.8 grams of 50% sodium hydroxide solution, and an additional 4.6 grams of water were added to the solution in the reactor. A monomer solution containing 36.2 grams of acrylic acid and 150 grams of water was subsequently added to the reactor over a period of 4 hours. An initiator solution comprised of 19.4 grams of 35% hydrogen peroxide solution, and 150 grams of water was added to the reactor at the same time as the monomer solution over a period of 4 hours. The reaction product was held at 98° C. for an additional 60 minutes. The final product was a brown solution. The number of reacted anhydroglucose units per every 100 anhydroglucose units was found to be 32.6 using the procedure detailed in Example 2.

Example 5

112.6 grams of maltodextrin as a polysaccharide as a natural component (STAR-DRI 100 DE 10 spray-dried maltodextrin available from Tate and Lyle, Decatur, Ill.) and 24.2 grams of maleic anhydride were initially dissolved in 110 grams of water in a reactor and heated to 98° C. 0.0012 g of ferrous ammonium sulfate hexahydrate and 24.8 grams of 50% sodium hydroxide solution were added to the solution in the reactor. A monomer solution containing 36.2 grams of acrylic acid and 150 grams of water was subsequently added to the reactor over a period of 4 hours. An initiator solution comprised of 5.21 grams of 35% hydrogen peroxide solution in 150 grams of water was added to the reactor at the same time as the monomer solution over a period of 4 hours. The reaction product was held at 65° C. for an additional 60 minutes. The final product was a dark amber solution. The number of reacted anhydroglucose units per every 100 anhydroglucose units was found to be 5.5 using the procedure detailed in Example 2.

Example 6

150 grams of maltodextrin as a polysaccharide as a natural component (STAR-DRI 180 DE 18 spray-dried maltodextrin available from Tate and Lyle, Decatur, Ill.) was initially dissolved in 380 grams of water in a reactor and heated to 98° C. 0.0015 g of ferrous ammonium sulfate hexahydrate was added to the solution in the reactor. A monomer solution containing 50 grams of acrylic acid was subsequently added to the reactor over a period of 90 minutes. An initiator solution comprised of 7.2 grams of 35% hydrogen peroxide solution in 60 grams of water was added to the reactor at the same time as the monomer solution over a period of 90 minutes. The reaction product was held at 98° C. for an additional 60 minutes. The final product was a clear white solution. The number of reacted anhydroglucose units per every 100 anhydroglucose units was found to be less than 1 using the procedure detailed in Example 2.

Example 7

38 grams of maltodextrin as a polysaccharide as a natural component (STAR-DRI 180 DE 18 spray-dried maltodextrin, Mw 25653, Mn 13744, available from Tate and Lyle, Decatur, Ill.) and 0.0024 grams of ferrous ammonium sulfate hexahydrate were initially dissolved in 160 grams of water in a reactor and heated to 98° C. A monomer solution containing 62.8 grams of acrylic acid and 99.4 grams of 50% AMPS solution was subsequently added to the reactor over a period of 120 minutes. An initiator solution comprised of 11.3 grams of 35% hydrogen peroxide in 50 grams of water was added to the reactor at the same time as the monomer solution over a period of 120 minutes. The reaction product was held at 98° C. for an additional 60 minutes. The final product was a clear yellow solution. The number of reacted anhydroglucose units per every 100 anhydroglucose units was found to be 12.6 using the procedure detailed in Example 2. The polymer gave 90% phosphate inhibition at 22 ppm polymer using the procedure of Example 1 of U.S. Pat. No. 5,547,612.

Example 8

The number of reacted anhydroglucose units per 100 anhydroglucose units in a series of graft copolymers containing polysaccharides were determined by the procedure detailed in Example 2 (see Table 6).

TABLE 6 Polymer # of reacted of Natural AGU's per Percent CO₃ Inhibition Example Component 100 AGU's 10 ppm 15 ppm 1 DE 10 11.9 69.0 93.0 maltodextrin 3 DE 10 13.5 99.0 99.0 maltodextrin 4 DE 42 corn 32.6 93.0 99.0 syrup 5 DE 10 5.5 53.0 80.0 maltodextrin 6 DE 18 <1 19.0 30.0 maltodextrin These data indicate that the polymers having 4 or more reacted anhydroglucose units per every 100 anhydroglucose units have good to acceptable performance carbonate inhibition performance when tested using the procedure of described in the specification. However, polymers (see Examples 6) having less than 4 reacted anhydroglucose units per every 100 anhydroglucose units do not have good performance.

Example 9

30.6 grams of a oxidized starch containing 18 mole % carboxylic acid and 10 mole % aldehyde functionality with a weight average molecular weight of 49,000 and a number average molecular weight of 12,500 and 6.6 grams of maleic anhydride were initially dissolved in 100 grams of water in a reactor and heated to 98° C. 0.002 g of ferrous ammonium sulfate hexahydrate, 6.6 grams of 50% sodium hydroxide solution, and 13.77 grams of sodium chloride were added to the solution in the reactor. A monomer solution containing 9.86 grams of acrylic acid and 200 grams of water was subsequently added to the reactor over a period of 4 hours. An initiator solution comprised of 5.8 grams of 35% hydrogen peroxide solution, and 200 grams of water was added to the reactor at the same time as the monomer solution over a period of 4.25 hours. The reaction product was held at 98 C for 60 minutes. The final product was a dark amber solution.

Example 10

30.6 grams of a oxidized starch containing 27 mole % carboxylic acid and 10 mole % aldehyde functionality with a weight average molecular weight of 62,000 and a number average molecular weight of 15,000 and 6.6 grams of maleic anhydride were initially dissolved in 100 grams of water in a reactor and heated to 98° C. 0.002 g of ferrous ammonium sulfate hexahydrate, 6.6 grams of 50% sodium hydroxide solution, and 13.77 grams of sodium chloride were added to the solution in the reactor. A monomer solution containing 9.86 grams of acrylic acid and 200 grams of water was subsequently added to the reactor over a period of 4 hours. An initiator solution comprised of 5.8 grams of 35% hydrogen peroxide solution, and 200 grams of water was added to the reactor at the same time as the monomer solution over a period of 4.25 hours. The reaction product was held at 98 C for 60 minutes. The final product was a light brown solution.

Example 11

The samples of Examples 9 and 10 were tested using the procedure detailed in Example 2. The analysis was corrected for the fact that the oxidized starch would give less glucose after hydrolysis than the unmodified maltodextrin of Example 2. These materials were tested for carbonate inhibition using the calcium carbonate inhibition test protocol as hereinbefore described.

TABLE 7 # of reacted AGU's per Percent CO₃ Inhibition Polymer 100 AGU's 10 ppm 15 ppm 9 45.2 87.7 87.9 10 26.5 86.8 90.2 These data indicate that the oxidized starches have a relative high amount of reacted AGU's per 100 AGU's and have good carbonate inhibition performance.

Example 12 Synthesis of Amphoteric Graft Copolymer

208.5 grams (27% aqueous solution) of RediBond 5330A (cationic undegraded starch available from National Starch and Chemical, Bridgewater, N.J.) as a natural component and 0.036 grams of alpha-amylase were initially dissolved in 100 grams of water in a reactor and heated to 40° C. to depolymerize the cationic starch. The pH of the solution was adjusted to pH 7.0 with 50% sodium hydroxide solution to stop the enzymatic degradation, and the mixture was allowed to cook for 1 hour. 0.004 g of Ferrous Ammonium Sulfate, 12.4 grams of 50% sodium hydroxide solution, 12.1 grams of maleic anhydride, and an additional 2.3 grams of water were added to the solution in the reactor, which was then heated to 98° C. A monomer solution containing 18.1 grams of acrylic acid and 75 grams of water was subsequently added to the reactor over a period of 4 hours. An initiator solution comprised of 9.7 grams of 35% hydrogen peroxide solution, and 75 grams of water was added to the reactor at the same time as the monomer solution over a period of 4 hours. The reaction product was cooled and held at 65° C. for an additional 60 minutes. The final product was a brown solution.

Example 13 Synthesis of Highly Renewable Graft Copolymer Containing Itaconic Acid and a Polysaccharide Natural Component

102.4 grams of maltodextrin as a polysaccharide as a natural component (STAR-DRI 100 DE 10 spray-dried maltodextrin available from Tate and Lyle, Decatur, Ill.) and 55.1 grams of itaconic acid was initially dissolved in 97.4 grams of water in a reactor and heated to 95° C. 0.006 g of ferrous ammonium sulfate hexahydrate and 27 grams of 50% sodium hydroxide solution was added to the solution in the reactor. An initiator solution comprised of 13.4 grams of 35% hydrogen peroxide solution dissolved in 150 grams of water was added to the reactor over a period of 4 hours. The reaction product was held at 98° C. for an additional 60 minutes. The final product was a dark brown solution. The amount of residual itaconic acid was found to be 3740 ppm of the solution or 3.0% of the monomer added to the reaction.

Comparative Example 1 Synthesis of Itaconic Acid Homopolymer

55.1 grams of itaconic acid was initially dissolved in 97.4 grams of water in a reactor and heated to 95° C. 0.006 g of ferrous ammonium sulfate and 27 grams of 50% sodium hydroxide solution was added to the solution in the reactor. An initiator solution comprised of 13.4 grams of 35% hydrogen peroxide solution dissolved in 90 grams of water was added to the reactor over a period of 4 hours. The reaction product was held at 98° C. for an additional 60 minutes. The final product was a dark brown solution. The amount of residual itaconic acid was found to be 1.05% of the solution or 54% of the monomer added to the reaction. The residual itaconic acid content in the homopolymer of this example is an order of magnitude higher than the highly renewable graft copolymer of Example 13 which shows that the itaconic acid based graft copolymers tend to graft on to a natural component better than reacting with itself.

Example 14 Synthesis of Anionic Graft Copolymer with Lignosulfonate

104 grams a lignosulfonate (ARBO S08 50% solution available from Tembec Chemical Products Group) was mixed with 25 grams of water and 0.003 grams of ferrous ammonium sulfate hexahydrate and heated to 94° C. A monomer solution containing 30 grams of acrylic acid and 40 grams of a 50% solution of Na 2-acrylamido-2-methyl propane sulfonate and 38 grams of water was subsequently added to the reactor over a period of 2 hours. An initiator solution comprising of 4.4 grams of a 35% hydrogen peroxide solution in 30 grams of water was added to the reactor at the same time as the monomer solution over a period of 2 hours. The reaction product was held at 94° C. for an additional 60 minutes. The final product was a dark amber/black colored solution.

Example 15 Synthesis of Ester Graft Copolymer Composition

32.9 grams of maleic anhydride was dissolved in 140 grams of water. 318 grams of a lignosulfonate (ARBO S08 50% solution available from Tembec Chemical Products Group) was added to the reactor. 33.4 grams of 50% sodium hydroxide solution was added and the mixture was heated to 87 C. 0.015 grams of ferrous ammonium sulfate hexahydrate dissolved in 6 grams of water was then added to the reactor. A monomer solution containing a mixture of 49.3 grams of acrylic acid in 6.4 grams of water was added to the reactor over a period of 4 hours. An initiator solution comprising of 28.9 grams of 35% hydrogen peroxide solution and 3.6 grams of sodium persulfate dissolved in 14 grams of water was added over a period of 4 hours. The reaction product was held at 87° C. for 60 minutes. The final product was a dark amber colored solution.

Example 16

The polymer of Example 14 was tested in a phosphate inhibition test described in Example 1 of U.S. Pat. No. 5,547,612.

TABLE 8 Polymer concentration Polymer (ppm) % phosphate inhibition Example 14 25 11 Example 14 50 95 Example 14 100 100

Calcium phosphate inhibition numbers above 80% are considered to be acceptable in this test. These data in Table 8 above indicate that the lignosulfonate graft copolymer of Example 14 is an excellent calcium phosphate inhibitor.

Example 17

The polymer of Example 15 was tested in a carbonate inhibition test described in in the specification.

TABLE 9 Polymer concentration Polymer (ppm) % carbonate inhibition Example 15 25 81

Calcium carbonate inhibition numbers above 80% are considered to be acceptable in this test. These data in Table 9 indicate that the polymers of this invention are good calcium carbonate inhibitors.

Lignosulfonate Anionic Graft Copolymer Based Detergent Formulations Example 18 Liquid Detergent Formulation

Ingredients wt % Linear alkyl benzene sulfonate 10 Alkyl sulfate 4 Alcohol (C₁₂-C₁₅) ethoxylate 12 Fatty acid 10 Oleic acid 4 Citric acid 1 NaOH 3.4 Propanediol 1.5 Ethanol 5 Polymer of Example 14 1 Ethanol oxidase 5 u/ml Water, perfume, minors up to 100

Example 19

An automatic zero phosphate dishwash formulation was formulated with a lignosulfonate anionic graft copolymer as shown in Table 10 below.

TABLE 10 A B Weight Weight Formulation percent percent tri-Sodium citrate − 2 H₂O 10-30 10-30 glutamic acid N,N-diacetic acid 15-35 15-35 (GLDA) or methylglycine N,N- diacetic acid (MGDA) Sodium carbonate 15-25 15-25 Sodium percarbonate 10 10 Sodium disilicate 5 5 TAED 5 5 Protease (e.g. Ovozyme 64T) 3 3 Amylase (e.g. Stainzyme 12T) 2 2 Polymer of Example LS 1 1-10 Polymer of Example 15 1-10 Synperonic 810 2.5 2.5 Synperonic 850 2.5 2.5 Sodium sulfate Rest Rest

Example 20 Automatic Non-Phosphate Dishwash Powder Formulation

Ingredients wt % Sodium citrate 30 Polymer of Example 14 10 Sodium disilicate 10 Perborate monohydrate 6 Tetraacetylethylenediamine 2 Enzymes 2 Sodium sulfate 30

Example 21 Automatic Dishwash Powder Formulation

Ingredients wt % Sodium tripolyphosphate 25.0 Sodium carbonate 25.0 Low foaming EO-PO block copolymer 1.0 to 3.0 Polymer of Example 15 4.0 Sodium sulfate rest

Example 22

104 grams of lignosulfonate (ARBO S08 50% solution available from Tembec Chemical Products Group) was added to 25 grams of water in a reactor and heated to 94° C. 0.003 grams of ferrous ammonium sulfate hexahydrate was added to the mixture in the reactor. A monomer solution containing 30 grams of acrylic acid and 40 grams of 50% sodium 2-acrylamido-2-methyl propane sulfonate in 38 grams of water was subsequently added to the reactor over a period of 2 hours. An initiator solution comprising of 4.4 grams 35% H₂O₂ solution in 60 grams of water was added to the reactor at the same time as the monomer solution over a period of 2 hours. The reaction product was held at 94° C. for an additional 60 minutes. The final product was a dark solution.

Example 23 Detection of Lignosulfonate Anionic Graft Copolymer

100, 10, and 1 ppm active polymer samples were prepared of the polymer in Example 22 in DI water. Solutions were analyzed with UV/VIS under the visible spectrum. Peak absorption occurred at 489 nm.

TABLE 11 Polymer of Polymer Example 22 concentration Absorbance at 489 ppm nm in a 1 cm cell 100 0.095 10 0.055 1 0.030

These data show that the lignosulfonate anionic graft copolymer can be easily detected by uv/vis. Thus the amount of polymer in an aqueous solution can be monitored. This allows the user to dose in the right amount of polymer in the aqueous treatment system and minimizes over dosing of the polymer

Example 24

613 grams of maltodextrin (STAR-DRI 100 DE 10 spray-dried maltodextrin available from Tate and Lyle, Decatur, Ill.) and 132 grams of maleic anhydride were initially dissolved in 482.5 grams of water in a reactor and heated to 98° C. 0.06 g of ferrous ammonium sulfate, 134.9 grams of 50% sodium hydroxide solution was added to the solution in the reactor. A monomer solution containing 198 grams of acrylic acid and 125 grams of water was subsequently added to the reactor over a period of 4 hour. An initiator solution comprised of 116 grams of 35% hydrogen peroxide solution in 60 grams of water was added to the reactor at the same time as the monomer solution over a period of 4.25 hours. The reaction product was held at 98° C. for an additional 60 minutes. The detectability of this polymer was measured as described below

A brine solution was prepared by adding 24.074 grams of sodium chloride, 1.61 grams of calcium chloride dehydrate, and 11.436 grams of magnesium chloride hexahydrate and dissolving in 962.88 grams of water. Diluted samples of the polymer above were prepared with this brine at 100, 50, 10, 5, 2, and 1 ppm levels of active polymer. To one mL of diluted polymer was added 1 mL of 5% phenol solution and 1 mL of concentrated sulfuric acid. Solutions were allowed to cool for one half hour, then analyzed with UV/VIS under the visible spectrum. The peak absorption was found to occur at 489 nm and all measurements were conducted at 489 nm.

TABLE 12 Polymer of Example 24 Polymer concentration Absorbance at 489 nm ppm Using 5% phenol in a 1 cm cell 100 0.553 50 0.371 10 0.254 5 0.148 2 0.143 1 0.089 These data indicate that the anionic graft copolymers can be detected in dilution solutions of as low as 1 ppm. The concentration of an unknown level of anionic graft copolymer can be detected by measuring the uv/vis absorbance of this polymer solution at 489 ppm and comparing this to the calibration curve in the Table 12 above.

Example 25

112.6 grams of maltodextrin as a natural component (Cargill 01904 DE 5 maltodextrin, Mw 1,24,788, Mn 39,593) and 24.2 grams of maleic anhydride were initially dissolved in 102 grams of water in a reactor and heated to 98° C. 0.008 g of ferrous ammonium sulfate, 24.8 grams of 50% sodium hydroxide solution, and an additional 4.6 grams of water were added to the solution in the reactor. A monomer solution containing 36.2 grams of acrylic acid and 150 grams of water was subsequently added to the reactor over a period of 4 hours. An initiator solution comprised of 2.4 grams sodium persulfate, 19.4 grams of 35% hydrogen peroxide solution, and 150 grams of water was added to the reactor at the same time as the monomer solution over a period of 4 hours. The reaction product was held at 98° C. for an additional 60 minutes. The final product was an inhomogeneous brown mixture. The polymer solution started to phase separate after a week. This indicates that natural components with a weight average molecular weight of above 100,000 do not form usable products as evidenced by the phase separation.

Example 26 Low Anionic Graft Copolymer

325.6 grams of maltodextrin (STAR-DRI 180 DE 18 spray-dried maltodextrin available from Tate and Lyle, Decatur, Ill.) and 12.31 grams of maleic anhydride were initially dissolved in 350 grams of water in a reactor and heated to 98° C. 0.005 g of ferrous ammonium sulfate, 1.88 grams of 50% sodium hydroxide solution, and 9.8 grams of water were added to the solution in the reactor. A monomer solution containing 69.1 grams of acrylic acid and 6.5 grams of water was subsequently added to the reactor over a period of 4 hours. An initiator solution comprised of 10.37 grams of 35% hydrogen peroxide solution in 150 grams of water was added to the reactor at the same time as the monomer solution over a period of 4 hours. The reaction product was held at 98° C. for an additional 60 minutes. This polymer was found to have good dispersancy.

Example 27 Low Anionic Graft Copolymer

200 grams of maltodextrin (STAR-DRI 180 DE 18 spray-dried maltodextrin available from Tate and Lyle, Decatur, Ill.) and 2 grams of maleic anhydride were initially dissolved in 180 grams of water in a reactor and heated to 98° C. 0.001 g of ferrous ammonium sulfate, 0.5 grams of 50% sodium hydroxide solution, and 9.8 grams of water were added to the solution in the reactor. A monomer solution containing 8 grams of acrylic acid and 65 grams of water was subsequently added to the reactor over a period of 1 hour. An initiator solution comprised of 2.22 grams of 35% hydrogen peroxide solution in 30 grams of water was added to the reactor at the same time as the monomer solution over a period of 1.25 hours. The reaction product was held at 98° C. for an additional 60 minutes. This polymer was found to have good dispersancy.

Example 28 Example of Amphoteric Graft Copolymer Using an Oxidized Cationic Starch and an Anionic Monomer

30 grams of cationic dent corn starch (containing 0.37 to 0.43% N) with 30 mole % oxidation was initially dissolved in 100 grams of water in a reactor and heated to 98° C. 0.0004 g of ferrous ammonium sulfate hexahydrate was added to the solution in the reactor. A monomer solution containing 10 grams of acrylic acid and 50 grams of water was subsequently added to the reactor over a period of 1 hour. An initiator solution comprised of 2 grams of 35% hydrogen peroxide solution and 50 grams of water was added to the reactor at the same time as the monomer solution over a period of 1 hour. The reaction product was held at 98° C. for an additional 60 minutes. The final product was a brown solution.

Example 29 Example of Amphoteric Graft Copolymer Using an Oxidized Starch and a Cationic Monomer

30 grams of degraded oxidized starch (Mw=43369) containing 1-2 mole % carboxylate functionality and 4-6 mole % aldehyde functionality was initially dissolved in 100 grams of water in a reactor and heated to 98° C. 0.0002 g of ferrous ammonium sulfate hexahydrate was added to the solution in the reactor. A monomer solution containing 16.1 grams of 67% diallyl dimethyl ammonium chloride (DADMAC) monomer solution and 50 grams of water was subsequently added to the reactor over a period of 1 hour. An initiator solution comprised of 0.9 grams of 35% hydrogen peroxide solution and 50 grams of water was added to the reactor at the same time as the monomer solution over a period of 1 hour. The reaction product was held at 98° C. for an additional 60 minutes. The final product was a brown solution.

Example 30

180 grams of a DE 10 maltodextrin with a weight average molecular weight Mw=62743 (STAR-DRI 100 DE 10 spray-dried maltodextrin available from Tate and Lyle, Decatur, Ill.) was initially dissolved in 380 grams of water in a reactor and heated to 98° C. 0.0011 g of ferrous ammonium sulfate hexahydrate was added to the solution in the reactor. A monomer solution containing 20 grams of acrylic acid was subsequently added to the reactor over a period of 90 minutes. An initiator solution containing 5.4 grams of 35% hydrogen peroxide solution in 60 grams of water was added to the reactor at the same time as the monomer solution over a period of 90 minutes. The reaction product was held at 98° C. for an additional 60 minutes.

Example 31

180 grams of DE 18 maltodextrin with a weight average molecular weight Mw=38215 (STAR-DRI 180 DE 18 spray-dried maltodextrin available from Tate and Lyle, Decatur, Ill.) was initially dissolved in 380 grams of water in a reactor and heated to 100° C. 0.0006 g of ferrous ammonium sulfate hexahydrate was added to the solution in the reactor. A monomer solution containing 20 grams of acrylic acid was subsequently added to the reactor over a period of 90 minutes. An initiator solution containing 2.9 grams of 35% hydrogen peroxide solution in 60 grams of water was added to the reactor at the same time as the monomer solution over a period of 90 minutes. The reaction product was held at 103° C. for an additional 60 minutes.

Example 32

150 grams of a DE 10 maltodextrin (STAR-DRI 100 DE 10 spray-dried maltodextrin available from Tate and Lyle, Decatur, Ill.) was initially dissolved in 380 grams of water in a reactor and heated to 100° C. 0.002 g of ferrous ammonium sulfate hexahydrate was added to the solution in the reactor. A monomer solution containing 50 grams of acrylic acid was subsequently added to the reactor over a period of 90 minutes. An initiator solution containing 10.1 grams of 35% hydrogen peroxide solution in 60 grams of water was added to the reactor at the same time as the monomer solution over a period of 90 minutes. The reaction product was held at 103° C. for an additional 60 minutes.

Example 33

150 grams of a DE 24 corn syrup (STAR-DRI 240 DE 24 spray-dried powder available from Tate and Lyle, Decatur, Ill.) was initially dissolved in 380 grams of water in a reactor and heated to 98° C. 0.0015 g of ferrous ammonium sulfate hexahydrate was added to the solution in the reactor. A monomer solution containing 50 grams of acrylic acid was subsequently added to the reactor over a period of 90 minutes. An initiator solution containing 7.2 grams of 35% hydrogen peroxide solution in 60 grams of water was added to the reactor at the same time as the monomer solution over a period of 90 minutes. The reaction product was held at 98° C. for an additional 60 minutes.

Example 34

150 grams of a DE 18 maltodextrin (STAR-DRI 180 DE 18 spray-dried maltodextrin available from Tate and Lyle, Decatur, Ill.) was initially dissolved in 380 grams of water in a reactor and heated to 86° C. 0.003 g of ferrous ammonium sulfate hexahydrate was added to the solution in the reactor. A monomer solution containing 50 grams of acrylic acid was subsequently added to the reactor over a period of 90 minutes. An initiator solution containing 13.5 grams of 35% hydrogen peroxide solution in 60 grams of water was added to the reactor at the same time as the monomer solution over a period of 90 minutes. The reaction product was held at 86° C. for an additional 60 minutes.

Example 35

0.004 g of ferrous ammonium sulfate hexahydrate was initially dissolved in 50 grams of water in a reactor and heated to 98° C. A monomer solution containing 10 grams of acrylic acid dissolved in 30 grams of water was subsequently added to the reactor over a period of 90 minutes. A solution of 14.4 grams of 35% hydrogen peroxide solution and 30 grams of Star Dri 180 in 360 grams of water was added to the reactor at the same time the monomer solution over a period of 90 minutes. The reaction product was held at 98° C. for an additional 60 minutes.

Example 36

100 grams of a DE 18 maltodextrin (STAR-DRI 180 DE 18 spray-dried maltodextrin available from Tate and Lyle, Decatur, Ill.) was initially dissolved in 380 grams of water in a reactor and heated to 98° C. 0.004 g of ferrous ammonium sulfate hexahydrate was added to the solution in the reactor. A monomer solution containing 100 grams of acrylic acid was subsequently added to the reactor over a period of 90 minutes. An initiator solution containing 20.2 grams of 35% hydrogen peroxide solution in 60 grams of water was added to the reactor at the same time as the monomer solution over a period of 90 minutes. The reaction product was held at 98° C. for an additional 60 minutes.

Example 37

The samples from Example 30 to 36 were analyzed for the number of reactive anhydroglucose units per 100 anhydroglucose units (#RAGU/100 AGU's) according to the method described in Example 2.

TABLE 13 Ferrous ammonium Acrylic Saccharide 35% H₂O₂ sulfate acid (g) (g) (g) hexahydrate normalized normalized normalized 6H₂O # to 100 g to 100 g to 100 g normalized Example RAGU/100 acrylic acrylic acrylic to 100 g Number AGU's acid acid acid acrylic acid 30 2.4 100 900 27.0 0.0055 31 4.4 100 900 14.5 0.0030 32 7 100 300 20.1 0.0040 33 6.2 100 300 14.2 0.0030 34 8 100 300 27.0 0.0060 35 11 100 300 144.0 0.030 36 12.6 100 100 20.2 0.0040

In addition, the weights of the acrylic acid in each of the reactions was normalized to 100 grams and the other ingredients was adjusted proportionately as detailed in Table 13. The moles of anhydroglucose (AGU) units was then calculated from the weight of the saccharide. The mole % of anhydroglucose (AGU) units was then calculated based on the total moles of AGU and monomer. The mole % peroxide/moles AGU was then calculated based on the moles of peroxide and moles of AGU. The μ moles metal ion catalyst/mole peroxide was then calculated and finally the μ moles metal ion catalyst/mole peroxide/mole AGU was calculated.

TABLE 14 μ moles metal μ moles moles metal ion # mole % metal ion catalyst/mole RAGU/100 moles mole % peroxide/moles ion catalyst/mole peroxide/mole Example # AGU's AGU AGU/(AGU + monomer) AGU catalyst peroxide AGU 30 2.4 5.556 80.00 0.050 15.4 55.6 10.0 31 4.4 5.556 80.00 0.027 8.4 56.5 10.2 32 7 1.852 57.14 0.112 11.2 54.3 29.3 33 6.2 1.852 57.14 0.079 8.4 57.6 31.1 34 8 1.852 57.14 0.150 16.9 60.6 32.7 35 11 1.852 57.14 0.800 84.3 56.8 30.7 36 12.6 0.617 30.77 0.337 11.2 54.0 87.5 The data in Table 14 indicate that if the mole % anhydroglucose units based on total moles of anhydroglucose units and monomer is greater than 75 we get a number of reacted anhydroglucose units per 100 anhydroglucose units less than 5. In addition, if the μ moles metal ion catalyst/mole peroxide/mole AGU is less than 15 the number of reacted anhydroglucose units per 100 anhydroglucose units is greater than 5.

All documents cited in the Detailed Description of the Invention are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention.

While particular embodiments of the present invention have been illustrated and described herein, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the range and scope of equivalents of the claims and without departing from the spirit and scope of the invention. 

1. An anionic graft copolymer comprising: a natural component grafted with an ethylenically unsaturated anionic monomer wherein the weight average molecular weight of the natural component is less than 100,000 and wherein the graft copolymer comprises 2 or more reacted anhydroglucose units per every 100 anhydroglucose units in the anionic graft copolymer.
 2. The anionic graft copolymer of claim 1 wherein the graft copolymer has an amount of μmoles of metal ion catalyst per mole peroxide per mole anhydroglucose unit from 2 to 87.5.
 3. The graft copolymer of claim 1 wherein the graft copolymer has a mole % of anhydroglucose units of from 10% to 75%.
 4. The anionic graft copolymer of claim 2 wherein the amount of μmoles of metal ion catalyst/mole peroxide/mole anhydroglucose unit is from 5 to 32.7.
 5. (canceled)
 6. The anionic graft copolymer of claim 1 wherein the molecular weight of the natural component is about 50,000 or less.
 7. The anionic graft copolymer of claim 1 wherein the natural component is selected from the group consisting of an oxidized starch, a maltodextrin, a corn syrup, a disaccharide and a monosaccharide.
 8. The anionic graft copolymer of claim 1 wherein the natural component is present from about 1% by weight to about 99% by weight, based on the total weight of the anionic graft copolymer.
 9. (canceled)
 10. The anionic graft copolymer of claim 1 wherein the natural component is present from about 20% by weight to about 99% by weight, based on the total weight of the anionic graft copolymer.
 11. The anionic graft copolymer of claim 1 wherein the natural component is present from about 50% by weight to about 99% by weight, based on the total weight of the anionic graft copolymer.
 12. (canceled)
 13. The anionic graft copolymer of claim 1 wherein the ethylenically unsaturated monomer is selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, 2-acrylamido-2-methyl propane sulfonic acid, salts thereof and mixtures thereof.
 14. A scale inhibiting composition comprising an anionic graft copolymer, wherein said anionic graft copolymer comprises: a natural component grafted with an ethylenically unsaturated anionic monomer wherein the anionic graft copolymer comprises 1 or more reacted anhydroglucose units per every 100 anhydroglucose units in the anionic graft copolymer, and wherein the composition has a greater than 80% carbonate inhibition at a 100 ppm dosage level of the anionic graft copolymer in an aqueous system.
 15. The scale inhibition composition of claim 14 wherein the anionic graft copolymer comprises 2 or more reacted anhydroglucose units per every 100 anhydroglucose units in the anionic graft copolymer.
 16. (canceled)
 17. The scale inhibiting composition of claim 14 wherein the natural component is selected from the group consisting of an oxidized starch, a maltodextrin, a corn syrup, a disaccharide and a monosaccharide.
 18. The scale inhibiting composition of claim 14 wherein the ethylenically unsaturated monomer is selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, 2-acrylamido-2-methyl propane sulfonic acid, salts thereof and mixtures thereof.
 19. The scale inhibiting composition of claim 14 wherein the natural component is a maltodextrin, and the ethylenically unsaturated monomer is acrylic acid, a salt of acrylic acid thereof or a mixture thereof.
 20. A method of inhibiting scale formation in an aqueous system, said method comprising adding to said aqueous system the scale inhibiting composition of claim
 14. 21. The method of claim 20 wherein the natural component is selected from the group consisting of an oxidized starch, a maltodextrin, a corn syrup, a disaccharide and a monosaccharide.
 22. The method of claim 20 wherein the ethylenically unsaturated monomer is selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, 2-acrylamido-2-methyl propane sulfonic acid, salts thereof and mixtures thereof.
 23. The method of claim 20 wherein the natural component is a maltodextrin, and the ethylenically unsaturated monomer is acrylic acid, a salt of acrylic acid thereof or a mixture thereof.
 24. A cleaning composition comprising the anionic graft copolymer of claim
 1. 25. A graft copolymer blend comprising: a graft copolymer, wherein the graft copolymer comprises a natural component grafted with an ethylenically unsaturated anionic monomer; and a builder or a chelating agent.
 26. The graft copolymer blend of claim 25 wherein the builder or chelating agent is selected from the group consisting of alkali metal or alkali-metal earth carbonates, alkali metal or alkali earth citrates, alkali metal or alkali earth silicates, glutamic acid N,N-diacetic acid (GLDA), methylglycine N,N-diacetic acid (MGDA) and combinations thereof.
 27. The graft copolymer blend of claim 25 wherein the natural component is a lignin or a derivative thereof.
 28. The graft copolymer blend of claim 27 wherein the natural component is lignosulfonate.
 29. An amphoteric graft copolymer comprising: a natural component comprising cationic or anionic moieties grafted with a cationic ethylenically unsaturated monomer or an anionic ethylenically unsaturated monomer or combinations thereof, whereby the resulting graft copolymer is amphoteric.
 30. The amphoteric graft copolymer of claim 29 wherein the natural component is an oxidized starch and the cationic ethylenically unsaturated monomer is diallyldimethylammonium chloride.
 31. The amphoteric graft copolymer of claim 29 wherein the natural component is an oxidized starch reacted with a cationic substituent prior to being grafted with the anionic or cationic ethylenically unsaturated monomer or mixtures thereof.
 32. The anionic graft copolymer of claim 1 wherein the graft copolymer comprises 2 to 12.6 reacted anhydroglucose units per every 100 anhydroglucose units in the anionic graft copolymer.
 33. The scale inhibiting composition of claim 14 wherein the anionic graft copolymer comprises 1 to 12.6 reacted anhydroglucose units per every 100 anhydroglucose units in the anionic graft copolymer. 